Pythia's Oasis
It has come to our attention at PNSN that there are several articles circulating online about the discovery of Pythia’s Oasis. Pythia’s Oasis is a seafloor seep off the coast of Central Oregon that was discovered in 2014 by researchers at UW Oceanography. A seafloor seep is a spot where, in this case, gasses and water that originate at depth are able to travel along a fault to the seafloor. For reliable information about this discovery, read this article written by UW News: https://www.washington.edu/news/2023/04/10/warm-liquid-spewing-from-oregon-seafloor-comes-from-cascadia-fault-could-offer-clues-to-earthquake-hazards/
Tabloid news sites have recently been circulating information about this discovery and claiming it is a harbinger of a large megathrust earthquake along the Cascadia Subduction Zone. This idea misrepresents what we actually learn from observations of Pythia’s Oasis and creates a false sense of alarm.
Figure 1: Sonar image of the gas bubbles being released by Pythia’s Oasis.
Though our knowledge of Pythia’s Oasis is somewhat new, it is one of many seeps that have undoubtedly existed for much, much longer than we have known about them. Scientists have known about offshore fluid seeps like Pythia’s Oasis since the 1980s - PNSN Director Harold Tobin worked on a similar seep as a graduate student. Pythia's Oasis happens to have a more vigorous flow than those previously discovered, but otherwise it is not much different. It was discovered in 2014 and explored in more detail in 2015, but there is nothing to suggest that Pythia’s Oasis itself is new or changing.
Figure 2: Images of water being released at Pythia’s Oasis.
Ultimately, this discovery is scientifically interesting but does not change anything about our understanding of the earthquake or tsunami hazard from the Cascadia Subduction Zone. We may learn some clues about the way tectonic stress builds up in this and similar faults, and about the temperature and pressure conditions deep inside that fault from the chemistry of the water flowing out of the sea bed. That insight could one day lead to better forecasting of the likelihood of earthquakes and tsunamis, but it does not change our overall understanding of the risk of an earthquake and is not in and of itself a cause for concern. The probability of a future Cascadia Subduction Zone major earthquake event still stands at about 15% likelihood in the next 50 years (estimated based on what we know about the history of prehistoric earthquakes).